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Part 2: Four Cheap 80 PLUS Bronze Power Supplies, Reviewed

At $45 And Up, We Reach For Power Supply Gold

Part one of our budget power supply round-up debated the merits of four PSUs ranging from 350 to 550 W, all of them flashing 80 PLUS Bronze ratings. Aside from the Cougar A350, all of them proved capable of satisfying the specification. Today we're looking at four more power supplies, this time ranging from 360 to 550 W. The range is a little narrower, but the contenders are all still quite comparable. Three sport the same Bronze logo, but one, Seasonic's SSR-360GP, boldly claims compliance with 80 PLUS' Gold standard, typically reserved for $100-plus products. All the while, the SSR-360GP sells for a mere $60.

Although that aggressive price gets our attention, we aren't going to neglect the other three test candidates: Cooler Master's Silent Pro M2 520W, Corsair's CX500, and Gigabyte's Greenmax Plus 450W. That Gigabyte unit doesn't seem to be available in the U.S., but with 550 W and 650 W versions showing up on Newegg, we're hoping to see the 450 W model soon.

As with yesterday's story, we again asses the sound levels of each PSU. This is something readers have been requesting for a while. Until now, though, we lacked a practical and reproducible methodology. From now on, we'll be measuring acoustics at three load levels: 40 W, which simulates an idle PC or a machine running office applications; 200 W, standing in for a mid-range gaming workload; and a 600 W draw to replicate what a more extreme gaming PC might encounter with a couple of graphics cards installed. That should get each unit's cooling fan spinning as fast as possible. Of course, if 600 W exceeds the maximum output of a power supply, we made do without it and simply use the other two.

In order to simulate these loads, we built a test fixture consisting of 12 V/40 W light bulbs, which imposes a purely resistive load on the power supply. With 15 lights, we can simulate any load between 40 W and 600 W, in 40 W steps. We are aware of the fact that a purely resistive load may stress a power supply differently than the partly capacitive, partly inductive load of a real-world PC. But we’re not overly worried; this synthetic load should be perfectly suited for measuring the sound level of the PSUs at each load level. Acoustics are measured one foot away from each power supply's fan, and we let each unit settle for half an hour any time we change the load.

Note that, in part one, we talked about a unique anomaly exhibited by one of our instruments. In short, after we upgraded oscilloscope probes to better ones, all of the PSUs we tested started showing spikes that the previous, less expensive probes never displayed. After some back-and-forth with a couple of power supply vendors, we came to the conclusion that our new probes allow us to pick up short spikes that the old ones missed.

  • Deemo13
    You guys aught to make a power supply hierarchy chart.
    Reply
  • pepsimtl
    Please, if you could say , if the power supply is compatible with Haswell .I think this is very important .
    Reply
  • benedict78
    I second that request. Does ANY of those PSUs support the new Haswell C7 state?
    Reply
  • ojas
    There's also a CX500M...
    Reply
  • jeffunit
    I am not sure why you think that a 40w bulb is purely resistive. Almost all bulb filaments are coiled, which makes them inductive. For example, http://www.donsbulbs.com/cgi-bin/r/b.pl/h4652|12.8v|40w|60w~usa.html shows a 12v 40w bulb filament, which is coiled.

    Perhaps you should measure the inductance of your bulbs, rather than just stating they are purely resistive.
    Reply
  • vertexx
    A couple different PSUs for different applications. I use the Corsair CX 430 & 500 for budget gaming builds, and just this week I ordered the Seasonic for the first time for a home server build. Nice to see those choices validated.

    Thanks guys, nice article!
    Reply
  • Someone Somewhere
    In spite of its low price, no important components fall victim to cost cutting.

    In the CX500. I think Samxon caps count as cost cutting.
    Reply
  • flong777
    I have recommended the CX500 many times to budget builders and now I feel better about it. It is the clear winner. Funny TH says it is loud but it was nearly identical to the CM 520 on their chart in DB noise.

    On sale you can pick up the CX500 for $40 which is about as cheap as you will ever find any PSU. If you compare how well that Corsair backs its products, there really is no comparison - Corsair is the only choice.

    As far as the Seasonic 360, why on earth would you buy a 360W PSU? I just don't see the point. While I can justify a 500W PSU to a budget builder, I really cannot comprehend recommending a 360W PSU to anyone. I feel cautious with a low wattage 500W PSU. All of these PSUs will run hot and loud if they are stressed and so moving up to a 650W or even an 850W PSU really is not that more expensive.

    I got the gold rated 850W Corsair HX 850 for $144.00 on sale. I can not even begin to describe how excellent this PSU is. It runs as something around 92% efficiency under load and I have never hear the fan even come on (it may be that low fan is inaudible). It comes with a 7-year warranty and is modular.

    If you are not strapped with a low budget, moving up is the only way to go. If you are, the CX 500 is a good choice.

    Reply
  • vertexx
    11443584 said:
    As far as the Seasonic 360, why on earth would you buy a 360W PSU? I just don't see the point. While I can justify a 500W PSU to a budget builder, I really cannot comprehend recommending a 360W PSU to anyone.
    I just ordered the Seasonic for a home server build. The higher efficiency is a plus since it will be running 24x7. Plus, the system really doesn't need the extra wattage.

    PSUs run more efficiently under load. IMO, the trend has been to overkill on the PSU when it's not really needed. In reality, when you actually add up the max loads of all components a 350-450W PSU is more than enough to run most single GPU gaming builds.
    Reply
  • vertexx
    11443366 said:
    I am not sure why you think that a 40w bulb is purely resistive. Almost all bulb filaments are coiled, which makes them inductive. For example, http://www.donsbulbs.com/cgi-bin/r/b.pl/h4652|12.8v|40w|60w~usa.html shows a 12v 40w bulb filament, which is coiled.

    Perhaps you should measure the inductance of your bulbs, rather than just stating they are purely resistive.
    It's been a while since I've been involved in DC power calculations, but these bulbs are DC bulbs. At DC steady state, what role does inductance play?
    Reply